This invention relates to an apparatus capable of generating finely divided particulate bubbles in a liquid.
Conventional apparatuses capable of supplying relatively fine bubbles into a liquid are well known. For example, a pneumatic pump for the cultivation of fish, power compressors and the like. However, none of them is free from the disadvantages of low efficiency and large physical size.
To cope with the problems of the conventional apparatuses, this inventor proposed previously a gas-liquid mixing apparatus having a simple construction but a high efficiency. As shown in FIG. 1, two flat plate-like discs D.sub.1 and D.sub.2 are fitted to the lower end of a straight hollow shaft P with a substantially uniform, relatively narrow gap G between the entire opposed surfaces of these discs in fluid communication with the hollow portion of the shaft P at its radial center. On one surface of either of the discs are disposed equidistantly and radially from the center a plurality of tapered separator plates S, with a proper gap therebetween. A disc D.sub.3 having liquid jet sections O formed around the circumference of the disc and is fitted to the separator plates S coaxially with the hollow shaft P.
When the portion of the discs D.sub.1 -D.sub.3 is dipped into a liquid, the hollow shaft P in communication with the gaseous phase is rotated at a high speed by means of a motor, etc., whereby the discs D.sub.1 -D.sub.3 start rotating. Consequently, the liquid present in the gap defined by these discs is imparted with a large kinetic force and caused to flow out towards the circumference of the discs, creating a vigorous flow of liquid from the intake port I of the disc D.sub.3 to the jet sections O around the circumference. Due to the high speed revolution, a large negative pressure is generated around the entire outer circumference of the gap G whereby the gas is sucked into the liquid and thus admixed therewith.
In the apparatus described above, the discs D.sub.1 -D.sub.3 are integrated to form a "disc body" and a high level of accuracy is required for the rotary balance of the disc body. Since the disc body is integrally and inseparably formed by the discs via the separator plates S and the shaft P, however, the production of a well-balanced disc body involves considerable technical difficulty. Because of its specific shape, the disc body is by no means easy to mass-produce without causing the increase in the cost of production. Moreover, since the disc body as a whole is rotated in a liquid, it has a large contact surface with the liquid and hence, a large resistance to rotation. Especially, the liquid jet section around the outer circumference of the disc D.sub.3 is formed in such a sectional shape as to obtain the effect of an expanded pipe at the time of outflow of the liquid. Since this portion also is rotated with the disc body, it results in the disadvantage that an additional load is applied to a driving source.
It is an object of the present invention to obviate those problems and to provide a novel apparatus which has an improved construction greatly facilitating production techniques, and is able to maintain the gas suction efficiency at a high level to thereby convert the gas into fine particulate bubbles and to admix the bubbles into a liquid.